Hero Motocorp — refund the amount

I was reach m/s. Bharat motors
Near state bank of india, kalagarh road, dhampur, uttar pradesh - 246746 to change speedometer sensor. Sensor was under warranty but they said to pay sensor charge. I pay and then senior officer said that sensor is under warranty and your paid amount will be refund on next service and give a paper note regarding refund amount. After 3 days, i receive a call from service center and he said that your sensor is not under warranty and paid amount will not refund.
Now my problem is, why they don't declare that sensor is not under warranty when i was present in service center. They declare sensor out of warranty when i was not in center. I want refund my sensor paid amount. Please take action as soon as possible.
Thank you.
Person contact number who call me that sensor is not under warranty is - [protected]
Bike registration number - dl 3s ds 8668
Name - daanish ali